Stochastic groundwater traveltime modeling using a Monte Carlo technique
A method of stochastically modeling groundwater traveltimes is described. This method is based on a Monte Carlo technique, which is used to generate a suite of random spatial fields. These fields are subsequently input to the groundwater flow and groundwater traveltime equations. Uncertain inputs to these equations can be: (1) transmissivity (or hydraulic conductivity); (2) effective thickness (or effective porosity); and (3) boundary conditions. In a transient problem, the storage coefficient (or specific storage) could also be stochastically treated. Spatial correlation in the random input fields is accounted for by means of a multivariate normal random-number generator, which requires that the first two statistical moments of these fields be specified. The output from the Monte Carlo analysis is a suite of random groundwater traveltime realizations that can be subsequently used to derive exceedance probabilities. These probabilities provide a means of assessing the degree of confidence in the groundwater traveltime predictions. An example of how to apply this method using available preliminary field data from the deep basalts beneath the US Department of Energy's Hanford Site in south-central Washington State is presented. The results from this type of analysis will ultimately be utilized in assessing the confidence in complying with a technical criterion relating to groundwater traveltime. Sensitivity analyses illustrate how these results change when some of the stochastic inputs are varied, and provide an emprical measure of how to optimally apply the method. This type of analysis will be updated as more field data become available. 22 refs., 5 figs.
- Research Organization:
- Rockwell International Corp., Richland, WA (USA). Rockwell Hanford Operations
- DOE Contract Number:
- AC06-77RL01030
- OSTI ID:
- 5750605
- Report Number(s):
- RHO-BW-SA-366P; CONF-850101-10; CONF-850170-1; ON: DE85009752
- Country of Publication:
- United States
- Language:
- English
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12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
BASALT
COMPUTERIZED SIMULATION
FEDERAL REGION X
FLUID FLOW
GROUND WATER
HYDRAULIC CONDUCTIVITY
HYDROGEN COMPOUNDS
IGNEOUS ROCKS
MONTE CARLO METHOD
NORTH AMERICA
OXYGEN COMPOUNDS
POROSITY
ROCKS
SENSITIVITY ANALYSIS
SIMULATION
STOCHASTIC PROCESSES
USA
VOLCANIC ROCKS
WASHINGTON
WATER